A controller for controlling a control target device by repeatedly executing a user program generated by a user in every predetermined period may use a method known in the art for editing a user program (online editing) or specifically changing a part of a currently running user program.
For example, Patent Literature 1 describes a programmable logic controller (PLC) having the online editing function of rewriting an object code stored in the PLC using an object code part generated by compiling a part of the source program.